Closes rails/rails#18864: Renaming transactional fixtures to transactional tests

I’m renaming all instances of `use_transcational_fixtures` to
`use_transactional_tests` and “transactional fixtures” to
“transactional tests”.

I’m deprecating `use_transactional_fixtures=`. So anyone who is
explicitly setting this will get a warning telling them to use
`use_transactional_tests=` instead.

I’m maintaining backwards compatibility—both forms will work.
`use_transactional_tests` will check to see if
`use_transactional_fixtures` is set and use that, otherwise it will use
itself. But because `use_transactional_tests` is a class attribute
(created with `class_attribute`) this requires a little bit of hoop
jumping. The writer method that `class_attribute` generates defines a
new reader method that return the value being set. Which means we can’t
set the default of `true` using `use_transactional_tests=` as was done
previously because that won’t take into account anyone using
`use_transactional_fixtures`. Instead I defined the reader method
manually and it checks `use_transactional_fixtures`. If it was set then
it should be used, otherwise it should return the default, which is
`true`. If someone uses `use_transactional_tests=` then it will
overwrite the backwards-compatible method with whatever they set.

1 files changed, 20 insertions, 8 deletions

diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 18775caad2..2c1771dd6c 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -139,13 +139,13 @@ module ActiveRecord
   #       name: kitten.png
   #       sha: <%= file_sha 'files/kitten.png' %>
   #
-  # = Transactional Fixtures
+  # = Transactional Tests
   #
   # Test cases can use begin+rollback to isolate their changes to the database instead of having to
   # delete+insert for every test case.
   #
   #   class FooTest < ActiveSupport::TestCase
-  #     self.use_transactional_fixtures = true
+  #     self.use_transactional_tests = true
   #
   #     test "godzilla" do
   #       assert !Foo.all.empty?
@@ -159,14 +159,14 @@ module ActiveRecord
   #   end
   #
   # If you preload your test database with all fixture data (probably in the rake task) and use
-  # transactional fixtures, then you may omit all fixtures declarations in your test cases since
+  # transactional tests, then you may omit all fixtures declarations in your test cases since
   # all the data's already there and every case rolls back its changes.
   #
   # In order to use instantiated fixtures with preloaded data, set +self.pre_loaded_fixtures+ to
   # true. This will provide access to fixture data for every table that has been loaded through
   # fixtures (depending on the value of +use_instantiated_fixtures+).
   #
-  # When *not* to use transactional fixtures:
+  # When *not* to use transactional tests:
   #
   # 1. You're testing whether a transaction works correctly. Nested transactions don't commit until
   #    all parent transactions commit, particularly, the fixtures transaction which is begun in setup
@@ -835,13 +835,15 @@ module ActiveRecord
       class_attribute :fixture_path, :instance_writer => false
       class_attribute :fixture_table_names
       class_attribute :fixture_class_names
+      class_attribute :use_transactional_tests
       class_attribute :use_transactional_fixtures
       class_attribute :use_instantiated_fixtures # true, false, or :no_instances
       class_attribute :pre_loaded_fixtures
       class_attribute :config
 
+      singleton_class.deprecate 'use_transactional_fixtures=' => 'use use_transactional_tests= instead'
+
       self.fixture_table_names = []
-      self.use_transactional_fixtures = true
       self.use_instantiated_fixtures = false
       self.pre_loaded_fixtures = false
       self.config = ActiveRecord::Base
@@ -849,6 +851,16 @@ module ActiveRecord
       self.fixture_class_names = Hash.new do |h, fixture_set_name|
         h[fixture_set_name] = ActiveRecord::FixtureSet.default_fixture_model_name(fixture_set_name, self.config)
       end
+
+      silence_warnings do
+        define_singleton_method :use_transactional_tests do
+          if use_transactional_fixtures.nil?
+            true
+          else
+            use_transactional_fixtures
+          end
+        end
+      end
     end
 
     module ClassMethods
@@ -919,13 +931,13 @@ module ActiveRecord
     end
 
     def run_in_transaction?
-      use_transactional_fixtures &&
+      use_transactional_tests &&
         !self.class.uses_transaction?(method_name)
     end
 
     def setup_fixtures(config = ActiveRecord::Base)
-      if pre_loaded_fixtures && !use_transactional_fixtures
-        raise RuntimeError, 'pre_loaded_fixtures requires use_transactional_fixtures'
+      if pre_loaded_fixtures && !use_transactional_tests
+        raise RuntimeError, 'pre_loaded_fixtures requires use_transactional_tests'
       end
 
       @fixture_cache = {}